RFIC with on-chip acoustic transducer circuit

ABSTRACT

An RFIC includes a transmit acoustic transducer, a digital conversion module, a transmit baseband module, an analog conversion module, an up-conversion module, a power amplifier circuit, a low noise amplifier circuit, a down-conversion module, a receive baseband processing module, and a receive acoustic transducer circuit. The transmit acoustic transducer circuit converts transmit sound waves into transmit electrical signals. The digital conversion module converts the transmit electrical signals into digital transmit audio signals and converts down-converted signals into digital receive baseband or low IF signals. The transmit baseband processing module converts the digital transmit audio signals into digital transmit baseband or low IF signals. The analog conversion module converts the digital transmit baseband or low IF signals into analog transmit baseband or low IF signals and converts digital receive audio signals into receive electrical signals. The up-conversion module converts the analog transmit baseband or low IF signals into up-converted signals. The power amplifier circuit amplifies the up-converted signals. The low noise amplifier circuit amplifies receive RF signals. The down-conversion module converts the amplified receive RF signals into the down-converted signals. The receive baseband processing module converts the digital receive baseband or low IF signals into the digital receive audio signals. The receive acoustic transducer circuit converts the receive electrical signals into receive sound waves.

CROSS REFERENCE TO RELATED APPLICATION

This application is a continuation of and claims priority to U.S. patentapplication having an application Ser. No. 11/513,588, filed Aug. 31,2006, which application is incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Technical Field of the Invention

This invention relates generally to wireless communication systems andmore particularly to wireless communication devices.

2. Description of Related Art

Communication systems are known to support wireless and wire linedcommunications between wireless and/or wire lined communication devices.Such communication systems range from national and/or internationalcellular telephone systems to the Internet to point-to-point in-homewireless networks. Each type of communication system is constructed, andhence operates, in accordance with one or more communication standards.For instance, wireless communication systems may operate in accordancewith one or more standards including, but not limited to, IEEE 802.11,Bluetooth, ZigBee, advanced mobile phone services (AMPS), digital AMPS,global system for mobile communications (GSM), code division multipleaccess (CDMA), local multi-point distribution systems (LMDS),multi-channel-multi-point distribution systems (MMDS), radio frequencyidentification (RFID), and/or variations thereof.

Depending on the type of wireless communication system, a wirelesscommunication device, such as a cellular telephone, two-way radio,personal digital assistant (PDA), personal computer (PC), laptopcomputer, home entertainment equipment, RFID reader, RFID tag, et ceteracommunicates directly or indirectly with other wireless communicationdevices. For direct communications (also known as point-to-pointcommunications), the participating wireless communication devices tunetheir receivers and transmitters to the same channel or channels (e.g.,one of the plurality of radio frequency (RF) carriers of the wirelesscommunication system or a particular RF frequency for some systems) andcommunicate over that channel(s). For indirect wireless communications,each wireless communication device communicates directly with anassociated base station (e.g., for cellular services) and/or anassociated access point (e.g., for an in-home or in-building wirelessnetwork) via an assigned channel. To complete a communication connectionbetween the wireless communication devices, the associated base stationsand/or associated access points communicate with each other directly,via a system controller, via the public switch telephone network, viathe Internet, and/or via some other wide area network.

For each wireless communication device to participate in wirelesscommunications, it includes a built-in radio transceiver (i.e., receiverand transmitter) or is coupled to an associated radio transceiver (e.g.,a station for in-home and/or in-building wireless communicationnetworks, RF modem, etc.). As is known, the receiver is coupled to theantenna and includes a low noise amplifier, one or more intermediatefrequency stages, a filtering stage, and a data recovery stage. The lownoise amplifier receives inbound RF signals via the antenna andamplifies then. The one or more intermediate frequency stages mix theamplified RF signals with one or more local oscillations to convert theamplified RF signal into baseband signals or intermediate frequency (IF)signals. The filtering stage filters the baseband signals or the IFsignals to attenuate unwanted out of band signals to produce filteredsignals. The data recovery stage recovers raw data from the filteredsignals in accordance with the particular wireless communicationstandard.

As is also known, the transmitter includes a data modulation stage, oneor more intermediate frequency stages, and a power amplifier. The datamodulation stage converts raw data into baseband signals in accordancewith a particular wireless communication standard. The one or moreintermediate frequency stages mix the baseband signals with one or morelocal oscillations to produce RF signals. The power amplifier amplifiesthe RF signals prior to transmission via an antenna.

In many applications of a radio transceiver, the raw data that istransmitted and/or received includes digitized audio signals (e.g.,digitized voice, music files such as MP3 files, video files such as MPEGfiles, and/or a combination thereof). As is known, a microphone is usedto capture analog audio signals and a speaker is used to render analogaudio signals audible. As is known, analog audio signals captured by amicrophone are biased to a particular level, amplified, and digitized(i.e., converted to digital signals and may further be encoded inaccordance with an encoding format). As is further known, digitizedaudio signals are converted to analog audio signals, amplified via avolume control, and subsequently rendered audible by a speaker.

Recently, through the advent of Microelectromechanical Systems (MEMs), afew companies have developed microphone integrated circuits and speakerintegrated circuits. For example, Akustica, as claimed on its web page(Akustica.com), has developed an analog microphone chip (part no.AKU1000), a digital microphone chip (part no. AKU2000), and speakerchips. While integrated microphone chips and speaker chips offercommunication device manufacturers smaller form factors, the chips arestill separate components requiring printed circuit board (PCB) spaceand connections to and/or from other integrated circuits on the PCB.

Therefore, a need exists for a radio frequency integrated circuit thatincludes an on-chip acoustic transducer circuit.

SUMMARY OF THE INVENTION

The present invention is directed to apparatus and methods of operationthat are further described in the following Brief Description of theDrawings, the Detailed Description of the Invention, and the claims.Other features and advantages of the present invention will becomeapparent from the following detailed description of the invention madewith reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S)

FIG. 1 is a schematic block diagram of a wireless communication systemin accordance with the present invention;

FIG. 2 is a schematic block diagram of a radio transceiver in accordancewith the present invention;

FIGS. 3 and 4 are schematic block diagrams of various embodiments of atransmit acoustic transducer circuit in accordance with the presentinvention;

FIGS. 5 and 6 are schematic block diagrams of various embodiments of areceive acoustic transducer circuit in accordance with the presentinvention;

FIGS. 7-10 are schematic block diagrams of various embodiments of adigital conversion module in accordance with the present invention;

FIGS. 11-14 are schematic block diagrams of various embodiments of ananalog conversion module in accordance with the present invention;

FIG. 15 is a schematic block diagram of a radio transmitter integratedcircuit in accordance with the present invention; and

FIG. 16 is a schematic block diagram of a radio receiver integratedcircuit in accordance with the present invention.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 is a schematic block diagram illustrating a communication system10 that includes a plurality of base stations and/or access points 12,16, a plurality of wireless communication devices 18-32 and a networkhardware component 34. Note that the network hardware 34, which may be arouter, switch, bridge, modem, system controller, et cetera provides awide area network connection 42 for the communication system 10. Furthernote that the wireless communication devices 18-32 may be laptop hostcomputers 18 and 26, personal digital assistant hosts 20 and 30,personal computer hosts 24 and 32 and/or cellular telephone hosts 22 and28 that include a built in radio transceiver and/or have an associatedradio transceiver. The details of the radio transceiver will bedescribed in greater detail with reference to FIGS. 2-16.

Wireless communication devices 22, 23, and 24 are located within anindependent basic service set (IBSS) area and communicate directly(i.e., point to point). In this configuration, these devices 22, 23, and24 may only communicate with each other. To communicate with otherwireless communication devices within the system 10 or to communicateoutside of the system 10, the devices 22, 23, and/or 24 need toaffiliate with one of the base stations or access points 12 or 16.

The base stations or access points 12, 16 are located within basicservice set (BSS) areas 11 and 13, respectively, and are operablycoupled to the network hardware 34 via local area network connections36, 38. Such a connection provides the base station or access point 1216 with connectivity to other devices within the system 10 and providesconnectivity to other networks via the WAN connection 42. To communicatewith the wireless communication devices within its BSS 11 or 13, each ofthe base stations or access points 12-16 has an associated antenna orantenna array. For instance, base station or access point 12 wirelesslycommunicates with wireless communication devices 18 and 20 while basestation or access point 16 wirelessly communicates with wirelesscommunication devices 26-32. Typically, the wireless communicationdevices register with a particular base station or access point 12, 16to receive services from the communication system 10.

Typically, base stations are used for cellular telephone systems andlike-type systems, while access points, or master transceivers, are usedfor in-home or in-building wireless networks (e.g., IEEE 802.11 andversions thereof, Bluetooth, RFID, and/or any other type of radiofrequency based network protocol). Regardless of the particular type ofcommunication system, each wireless communication device includes abuilt-in radio and/or is coupled to a radio. Note that one or more ofthe wireless communication devices may include an RFID reader and/or anRFID tag.

FIG. 2 is a schematic block diagram of a radio frequency integratedcircuit (RFIC) that may be used in any of the wireless communicationdevices of FIG. 1 or as a radio frequency transceiver for any other RFapplication where audio signals are transmitted and/or received. TheRFIC includes a transmit acoustic transducer 100, a digital conversionmodule 102, a transmit baseband module 104, an analog conversion module106, an up-conversion module 108, a power amplifier circuit 110, a lownoise amplifier circuit 112, a down-conversion module 114, a receivebaseband processing module 115, and a receive acoustic transducercircuit 118.

The transmit acoustic transducer circuit 100 (embodiments of which willbe described in greater detail with reference to FIGS. 3 and 4) iscoupled to convert transmit sound waves 118 into transmit electricalsignals 120. The transmit sound waves 118, which may result from humanspeech and/or any other source that produces a wave transmitted throughthe air, cause mechanical vibrations within the transmit acoustictransducer circuit 100. The transmit acoustic transducer circuit 100converts the mechanical vibrations into the transmit electrical signals120.

The digital conversion module 102 (embodiments of which will bedescribed in greater detail with reference to FIGS. 7-10) is coupled toconvert the transmit electrical signals 120 into digital transmit audiosignals 122 when the RFIC is in a transmit mode. The digital transmitaudio signals 122 may be encoded in accordance with one or more encodingschemes, such as Pulse Code Modulation (PCM) A-law, PCM μ-law, andcontinuous variable slope delta demodulation. Note that the RFIC may bein the transmit mode via a transmit/receive mode signal 124, may be inthe transmit mode in accordance with a half duplex scheme where thetransmit path and receive path of the RFIC share a wirelesscommunication resource (e.g., one or more RF channels, use the same RFcarrier frequency, frequency hopping scheme, etc.), and/or may be in thetransmit mode simultaneously with the receive mode when the RFICsupports a full duplex scheme where the transmit path utilizes adifferent wireless communication resource than the receive path.

The transmit baseband processing module 104 is coupled to convert thedigital transmit audio signals 122 into digital transmit baseband or lowintermediate frequency (IF) signals 126 in accordance with one or morewireless communication standards. To achieve the conversion to thedigital transmit baseband or low IF signals 126, the transmit basebandprocessing module 104 may perform one or more transmitter functions uponthe digital transmit audio signals 122. The transmitter functionsinclude, but are not limited to, scrambling, encoding, puncturing,mapping, modulation, and/or digital baseband to IF conversion. Note thatthe baseband or low IF TX signals 164 may be digital baseband signals(e.g., have a zero IF) or digital low IF signals, where the low IFtypically will be in a frequency range of one hundred kilohertz to a fewmegahertz. Further note that the transmit baseband processing module 104and the receive baseband processing module 115 may be implemented usinga shared processing device, individual processing devices, or aplurality of processing devices and may further included associatedmemory. Such a processing device may be a microprocessor,micro-controller, digital signal processor, microcomputer, centralprocessing unit, field programmable gate array, programmable logicdevice, state machine, logic circuitry, analog circuitry, digitalcircuitry, and/or any device that manipulates signals (analog and/ordigital) based on operational instructions. The associated memory may bea single memory device or a plurality of memory devices. Such a memorydevice may be a read-only memory, random access memory, volatile memory,non-volatile memory, static memory, dynamic memory, flash memory, and/orany device that stores digital information. Note that when theprocessing module 104 and/or 116 implements one or more of its functionsvia a state machine, analog circuitry, digital circuitry, and/or logiccircuitry, the memory storing the corresponding operational instructionsis embedded with the circuitry comprising the state machine, analogcircuitry, digital circuitry, and/or logic circuitry.

The analog conversion module 106 (embodiments of which will be describedin greater detail with reference to FIGS. 11-14) is coupled to convertthe digital transmit baseband or low IF signals 126 into analog transmitbaseband or low IF signals 128 when the RFIC is in the transmit mode.

The up-conversion module 108 is coupled to convert the analog transmitbaseband or low IF signals 128, which may include in-phase componentsand quadrature components, into up-converted signals 132 based on atransmit local oscillation 130. The up-conversion module 108 may be adirect conversion module where the transmit local oscillation 130corresponds to the difference between the IF of the analog transmitbaseband or low IF signals 128 and the carrier frequency of the transmitRF signals 134. Alternatively, the up-conversion module 108 may be asuperheterodyne module where the transmit local oscillation 130 includestwo oscillations: one to convert the analog baseband or low IF signals128 into intermediate frequency signals and a second to convert theintermediate frequency signals into signals having the carrier frequencyof the transmit RF signals 134. Note that when the analog transmitbaseband or low IF signals 128 includes in-phase components andquadrature components, the transmit local oscillation 130 includes anin-phase component and a quadrature component such that the quadraturecomponent of the transmit local oscillation is mixed with the quadraturecomponents of the analog transmit baseband or low IF signals 128 and thein-phase component of the transmit local oscillation is mixed with thein-phase components of the analog transmit baseband or low IF signals128.

The power amplifier circuit 110 is coupled to amplify the up-convertedsignals to produce the transmit radio frequency (RF) signals 134. Thepower amplifier circuit 110 may include one or more power amplifiersand/or one or more pre-amplifiers coupled in series, in parallel orcombination thereof. The amplification provided by the power amplifiercircuit 110 is dependent upon the desired transmit power and whether anoff-chip power amplifier is used. The power amplifier circuit 110provides the transmit RF signals 134 to an antenna structure forover-the-air transmission.

The antenna structure may include a separate antenna(s) for the receivepath and the transmit path of the RFIC or the transmit and receive pathsmay share an antenna(s) via a transmit/receive switch and/or transformerbalun. In another embodiment, the receive and transmit paths may share adiversity antenna structure. In another embodiment, the receive andtransmit paths may each have its own diversity antenna structure. Inanother embodiment, the receive and transmit paths may share a multipleinput multiple output (MIMO) antenna structure. Accordingly, the antennastructure coupled to, or integrated on, the RFIC will depend on theparticular standard(s) to which the wireless transceiver is compliant.

The low noise amplifier (LNA) circuit 112 is coupled to amplify receiveRF signals 136 to produce amplified receive RF signals 138. The LNAcircuit 112 may include one or more amplifiers and/or one or morepre-amplifiers coupled in series, in parallel, or a combination thereofto amplify the receive RF signals 136 based on a gain setting. The gainsetting is at least partially dependent upon the signal strength of thereceive RF signals 136 and the desired operating range of the receivepath.

The down-conversion module 114 is coupled to convert the amplifiedreceive RF signals 138 into the down-converted signals 142 based on areceive local oscillation 140. The down-conversion module 114 may be adirect conversion module where the receive local oscillation 140corresponds to a difference between the IF of the down-converted signals142 (e.g., a zero IF or a low IF of a few Mega Hertz or less) and thecarrier frequency of the receive RF signals 136. Alternatively, thedown-conversion module 114 may be a superheterodyne module where thereceive local oscillation 140 includes two oscillations: one to convertthe receive RF signals 136 into intermediate frequency signals and asecond to convert the intermediate frequency signals into thedown-converted signals 142. Note that LNA circuit 112 may providein-phase components and quadrature components of the amplified receiveRF signals 138 to the down-conversion module 114. In this instance, thereceive local oscillation 140 includes an in-phase component and aquadrature component such that the quadrature component of the receivelocal oscillation 140 is mixed with the quadrature components of theamplified receive RF signals 138 and the in-phase component of thereceive local oscillation 140 is mixed with the in-phase components ofthe amplified receive RF signals 138.

The digital conversion module 102 converts the down-converted signals142 into digital receive baseband or low intermediate frequency (IF)signals 144 when the RFIC is in a receive mode. Note that the RFIC maybe in the receive mode via a transmit/receive mode signal 124, may be inthe receive mode in accordance with a half duplex scheme where thetransmit path and receive path of the RFIC share a wirelesscommunication resource (e.g., one or more RF channels, use the same RFcarrier frequency, frequency hopping scheme, etc.), and/or may be in thereceive mode simultaneously with the transmit mode when the RFICsupports a full duplex scheme where the transmit path utilizes adifferent wireless communication resource than the receive path.

The receive baseband processing module 115 is coupled to convert thedigital receive baseband or low IF signals 144 into the digital receiveaudio signals 146. To achieve the conversion to the digital receiveaudio signals 146, the receive baseband processing module 115 mayperform one or more receiver functions upon the digital receive basebandor low IF signals 144. The receiver functions include, but are notlimited to, digital intermediate frequency to baseband conversion,demodulation, demapping, depuncturing, decoding, and/or descrambling.Note that the digital receive baseband or low IF signals 144 may bedigital baseband signals (e.g., have a zero IF) or digital low IFsignals, where the low IF typically will be in a frequency range of onehundred kilohertz to a few megahertz.

The analog conversion module 106 converts the digital receive audiosignals 146 into receive electrical signals 148 when the RFIC is in thereceive mode. Such a conversion may include decoding using one or moredecoding schemes, which may include Pulse Code Modulation (PCM) A-law,PCM μ-law, and continuous variable slope delta demodulation.

The receive acoustic transducer circuit 116 (embodiments of which willbe described in greater detail with reference to FIGS. 3 and 4) iscoupled to convert the receive electrical signals 148 into receive soundwaves 150. The receive sound waves 150 are the result of mechanicalvibrations within the receive acoustic transducer circuit 116 inresponse to the receive electrical signals 148.

As one of ordinary skill in the art will appreciate, the RFIC may befabricated on a single die and placed within a conventional integratedcircuit (IC) package (e.g., ball grid array, surface mount, etc.).Alternatively, the RFIC may be fabricated on two dies that are placedwithin a single conventional IC package. For instance, a first die maysupport the transmit acoustic transducer circuit 100, the digitalconversion module 102, the transmit baseband processing module 104, theanalog conversion module 106, the receive baseband processing module115, and the receive acoustic transducer circuit 116 and a second diethat supports the up-conversion module 108, the power amplifier circuit110, the low noise amplifier circuit 112, and the down-conversion module114. As another alternative, the RFIC may be fabricated on two dies thatare placed in separate conventional IC package.

FIG. 3 is a schematic block diagram of an embodiment of the transmitacoustic transducer circuit 100 that includes a transducer 160 and abias circuit 162. The biasing circuit 162 is coupled to the transducer160 to provide a desired bias level for the transducer 160. Thetransducer 160, which may be a capacitive transducer, aMicroelectromechanical Systems (MEMs) microphone, and/or a floatingelectrode capacitive microphone, converts the transmit sounds waves 118into the transmit electrical signals 120 based on the biasing providedby the bias circuit 162.

FIG. 4 is a schematic block diagram of an embodiment of the transmitacoustic transducer circuit 100 that includes a plurality of transducers160-1 through 160-n and a biasing circuit 164. The plurality oftransducers 160-1 through 160-n may be coupled in parallel, coupled inan array, or function separately. When the plurality of transducers160-1 through 160-n are coupled in parallel, the bias circuit 164provides a common biasing to the transducers such that the transducersmay convert the transmit sounds waves 118 into the transmit electricalsignals 120. When the plurality of transducers 160-1 through 160-n arecoupled in an array, the bias circuit 164 provides a common biasing or abiasing based on the structure of the array to the transducers such thatthe transducers may convert the transmit sounds waves 118 into thetransmit electrical signals 120. When the plurality of transducers 160-1through 160-n function separately, the bias circuit 164 providesseparate biasing to the transducers such each of the transducersproduces electrical signals from the transmit sounds waves 118 and thebias circuit combines the electrical signals to produce the transmitelectrical signals 120. Note that the transducers 160-1 through 160-nmay be capacitive transducers, Microelectromechanical Systems (MEMs)microphones, and/or floating electrode capacitive microphones.

FIG. 5 is a schematic block diagram of an embodiment of the receiveacoustic transducer circuit 116 that includes a transducer 170 and abias circuit 172. The biasing circuit 172 is coupled to the transducer170 to provide a desired bias level for the transducer 170. Thetransducer 170, which may be a capacitive transducer, aMicroelectromechanical Systems (MEMs) speaker, and/or a floatingelectrode capacitive speaker, converts the receive electrical signals148 into the receive sounds waves 150 based on the biasing provided bythe bias circuit 172.

FIG. 6 is a schematic block diagram of an embodiment of the receiveacoustic transducer circuit 116 that includes a plurality of transducers170-1 through 170-n and a biasing circuit 174. The plurality oftransducers 170-1 through 170-n may be coupled in parallel, coupled inan array, or function separately. When the plurality of transducers170-1 through 170-n are coupled in parallel, the bias circuit 174provides a common biasing to the transducers such that the transducersmay convert the receive electrical signals 148 into the receive soundswaves 150. When the plurality of transducers 170-1 through 170-n arecoupled in an array, the bias circuit 174 provides a common biasing or abiasing based on the structure of the array to the transducers such thatthe transducers may convert the receive electrical signals 148 into thereceive sounds waves 150. When the plurality of transducers 170-1through 170-n function separately, the bias circuit 174 providesseparate biasing to the transducers such each of the transducersproduces sound waves from the receive electrical signals 148 as providedby the biasing circuit 174. Note that the transducers 170-1 through170-n may be capacitive transducers, Microelectromechanical Systems(MEMs) speakers, and/or floating electrode capacitive speakers.

FIG. 7 is a schematic block diagram of an embodiment of the digitalconversion module 102 that includes a multiplexer 176, an amplifier 170,an analog to digital conversion module 174, a multiplexer 178, and anaudio encoding module 180. The multiplexers 176 and 178, which may beswitches, gates, connection nodes, and/or multiplexers, are controlledby the status of the transmit/receive mode signal 124. Note that whenthe RFIC is in a half duplex mode, the transmit/receive mode signal 124may be inherent in the RFIC based on whether the transmit path is activeor the receive path is active. In this instance, the multiplexers 176and 178 may be implemented as the connection nodes (i.e., electricallyconnection with one line active and the other inactive in accordancewith the RFIC half duplex operation).

When the RFIC is in the transmit mode, multiplexer 176 provides thetransmit electrical signals 120 to the amplifier 170. The amplifier 170amplifies the transmit electrical signals 120 in accordance with apre-established gain setting or an automatic gain control setting toproduce amplified transmit electric signals 182. The analog to digitalconversion module 174, which may include one or more analog to digitalconverters, is coupled to convert the amplified transmit electricalsignals 182 into transmit digital signals 184. Multiplexer 178 providesthe transmit digital signals 184 to the audio encoding module 180.

The audio encoding module 180 may be a separate processing device fromthe transmit baseband processing module 104, may share a processingdevice with the transmit baseband processing module 104, or may be amodule within the transmit baseband processing module 104. Regardless ofthe specific implementation, the audio encoding module 180 perform oneor more types of audio encoding upon the transmit digital signals 184 toproduce the digital transmit audio signals 122. Such encoding includesA-law pulse code modulation, μ-law pulse code modulation, and/orcontinuous variable slope delta modulation. In one embodiment, the audioencoding module 180 includes an input for receiving an audio encodingselection signal 188 which indicates the particular type of audioencoding it is to perform.

When the RFIC is in the receive mode, the multiplexer 176 provides thedown-converted signals 142 to the amplifier 170. The amplifier 170amplifies the down-converted signals 142 in accordance with an automaticgain control setting to produce amplified down-converted signals 186.Note that if the down-converted signals 142 include in-phase componentsand quadrature components, the amplifier 170 includes an in-phaseamplifier to amplify the in-phase components and a quadrature amplifierto amplify the quadrature components.

The analog to digital conversion module 174 converts the amplifieddown-converted signals 186 into the digital receive baseband or low IFsignals 144. Note that when the down-converted signals 142 includein-phase components and quadrature components, the analog to digitalconversion module 174 includes an in-phase analog to digital converterto convert the in-phase components and a quadrature analog to digitalconverter to convert the quadrature components. Multiplexer 178 providesthe digital receive baseband or low IF signals 144 to the receivebaseband processing module 115.

FIG. 8 is a schematic block diagram of an embodiment of the digitalconversion module 102 that includes an amplifier 170, an analog todigital conversion (ADC) module 174, a an analog to digital conversionmodule 194, and the audio encoding module 180. In this embodiment, whenthe RFIC is in the transmit mode, the amplifier 170, ADC module 174, andthe audio encoding module 180 are active, while the ADC module 194 isinactive and when the RFIC is in the receive mode, the amplifier 170,ADC module 174, and the audio encoding module 180 are inactive, whilethe ADC module 194 is active.

When the RFIC is in the transmit mode, the amplifier 170 amplifies thetransmit electrical signals 120 in accordance with a pre-establishedgain setting or an automatic gain control setting to produce amplifiedtransmit electric signals 182. The analog to digital conversion module174, which may include one or more analog to digital converters, iscoupled to convert the amplified transmit electrical signals 182 intotransmit digital signals 184. The audio encoding module 180 perform oneor more types of audio encoding upon the transmit digital signals 184 toproduce the digital transmit audio signals 122. Such encoding includesA-law pulse code modulation, μ-law pulse code modulation, and/orcontinuous variable slope delta modulation. In one embodiment, the audioencoding module 180 includes an input for receiving an audio encodingselection signal 188 which indicates the particular type of audioencoding it is to perform.

When the RFIC is in the receive mode, the analog to digital conversionmodule 194 converts the down-converted signals 142 into the digitalreceive baseband or low IF signals 144. Note that when thedown-converted signals 142 include in-phase components and quadraturecomponents, the analog to digital conversion module 194 includes anin-phase analog to digital converter to convert the in-phase componentsand a quadrature analog to digital converter to convert the quadraturecomponents.

FIG. 9 is a schematic block diagram of an embodiment of the digitalconversion module 102 that includes amplifier 170, the analog to digitalconversion module 174, the audio encoding module 180, the analog todigital conversion module 194, amplifier 190 or digital amplifier 196.In this embodiment, when the RFIC is in the transmit mode, the amplifier170, ADC module 174, and the audio encoding module 180 are active, whilethe ADC module 194 and the amplifier 190 or digital amplifier 196 areinactive and when the RFIC is in the receive mode, the amplifier 170,ADC module 174, and the audio encoding module 180 are inactive, whilethe ADC module 194 and the amplifier 190 or digital amplifier 196 areactive.

When the RFIC is in the transmit mode, the amplifier 170 amplifies thetransmit electrical signals 120 in accordance with a pre-establishedgain setting or an automatic gain control setting to produce amplifiedtransmit electric signals 182. The analog to digital conversion module174, which may include one or more analog to digital converters, iscoupled to convert the amplified transmit electrical signals 182 intotransmit digital signals 184. The audio encoding module 180 perform oneor more types of audio encoding upon the transmit digital signals 184 toproduce the digital transmit audio signals 122. Such encoding includesA-law pulse code modulation, μ-law pulse code modulation, and/orcontinuous variable slope delta modulation. In one embodiment, the audioencoding module 180 includes an input for receiving an audio encodingselection signal 188 which indicates the particular type of audioencoding it is to perform.

When the RFIC is in the receive mode, the amplifier 190 amplifies thedown-converted signals 142 to produce amplified down-converted signals186. The analog to digital conversion module 194 converts the amplifieddown-converted signals 186 into the digital receive baseband or low IFsignals 144. Note that when the down-converted signals 142 includein-phase components and quadrature components, the analog to digitalconversion module 194 includes an in-phase analog to digital converterto convert the in-phase components and a quadrature analog to digitalconverter to convert the quadrature components. In an alternativeembodiment, the analog to digital conversion module 194 converts theamplified down-converted signals 186 into pre-amplified digital receivebaseband or low IF signals. The digital amplifier 196 amplifies thepre-amplified digital receive baseband or low IF signals to produce thedigital receive baseband or low IF signals 144.

FIG. 10 is a schematic block diagram of an embodiment of the digitalconversion module 102 that includes amplifier 170, a combining module200, the analog to digital conversion module 174, a separation module202, and the audio encoding module 180. In this embodiment, the RFIC isin a full duplex mode (i.e., simultaneously in the receive mode andtransmit mode) where the transmit path uses a different frequency rangethan the receive path.

In this embodiment, the amplifier 170 amplifies the transmit electricalsignals 120 based on a pre-determined gain setting and/or an automaticgain control setting to produce amplified transmit electrical signals120. The combining module 200 combines the amplified transmit electricalsignals with the down-converted signals 142 to produce combined signals204. For example, the combining module 200 may be a summation modulethat sums the amplified transmit electrical signals (e.g., cos(αt)) withthe down-converted signals 142 (e.g., cos(ω_(IF)t)) to produce thecombined signals (2 cos 1/2(αt+ω_(IF)t)cos 1/2(αt−ω_(IF)t)=cos² αt−sin²ω_(IF)t). Note that if the down-converted signals 142 include in-phaseand quadrature components, the combining module 200 may combine theamplified transmit electrical signals with the in-phase componentsand/or the quadrature components.

The analog to digital conversion module 174 converts the combinedsignals 204 into digital combined signals. The separation module 202separates the digital combined signals into the transmit digital signals184 and the digital receive baseband or low IF signals 144. In oneembodiment, the separation module 200 may include a first digital filterand a second digital filter. The first digital filter is tuned to passthe cos² αt component of the combined signals 204 while substantiallyattenuating the sin² ω_(IF)t component of the combined signals 204 andthe second digital filter is tuned to pass the sin² ω_(IF)t component ofthe combined signals 204 while substantially attenuating the cos² αtcomponent of the combined signals 204. The separation module 200 mayfurther include a digital square root function to obtain cos αt and sinω_(IF)t and may further include a digital 90° phase shift module tophase shift sin ω_(IF)t to obtain cos ω_(IF)t.

The audio encoding module 180 perform one or more types of audioencoding upon the transmit digital signals 184 to produce the digitaltransmit audio signals 122. Such encoding includes A-law pulse codemodulation, μ-law pulse code modulation, and/or continuous variableslope delta modulation. In one embodiment, the audio encoding module 180includes an input for receiving an audio encoding selection signal 188which indicates the particular type of audio encoding it is to perform.

FIG. 11 is a schematic block diagram of an embodiment of the analogconversion module 106 that includes an audio decoding module 210, amultiplexer 216, a digital to analog conversion module 212, amultiplexer 218, and an amplifier 214. The multiplexers 216 and 218,which may be switches, gates, connection nodes, and/or multiplexers, arecontrolled by the status of the transmit/receive mode signal 124. Notethat when the RFIC is in a half duplex mode, the transmit/receive modesignal 124 may be inherent in the RFIC based on whether the transmitpath is active or the receive path is active. In this instance, themultiplexers 216 and 218 may be implemented as the connection nodes(i.e., electrically connection with one line active and the otherinactive in accordance with the RFIC half duplex operation).

When the RFIC is in the receive mode, the audio decoding module 210decodes the digital receive audio signals 146 in accordance with anaudio decoding scheme, which may be A-law pulse code demodulation, μ-lawpulse code demodulation, and continuous variable slope deltademodulation. In one embodiment, the audio decoding module 210 mayinclude an input for receiving an audio decoding selection signal 212that indicates the particular type of audio decoding to be performed.Note that the audio decoding module 210 may be a separate processingdevice from the receive baseband processing module 116, may share aprocessing device with the receive baseband processing module 116, ormay be a module within the receive baseband processing module 116.

In the receive mode, multiplexer 216 provides the decoded receive audiosignals from the audio decoding module 210 to the digital to analogconversion (DAC) module 212. The DAC module 212 may include one or moredigital to analog converts to convert the decoded receive audio signalsinto analog decoded audio signals. The amplifier 214 amplifies theanalog decoded audio signals in accordance with a pre-determined gainsetting and/or an automatic gain control setting to produce the receiveelectrical signals 148.

When the RFIC is in the transmit mode, multiplexer 216 provides thedigital transmit baseband or low IF signals 126 to the DAC module 212.The transmit baseband or low IF signals 126 may include in-phasecomponents and quadrature components. In such an instance, the DACmodule 212 would include two digital to analog converters: one for thein-phase components and another for the quadrature components. Onceconverted, multiplexer 218 provides the analog transmit baseband or lowIF signals 128 to the up-conversion module 108. Note that the analogtransmit baseband or low IF signals 128 may be amplified and/or filteredprior to or after multiplexer 218.

FIG. 12 is a schematic block diagram of an embodiment of the analogconversion module 106 that includes an audio decoding module 210, amultiplexer 216, a digital to analog conversion module 212, amultiplexer 218, and an amplifier 214. This embodiment is similar to theembodiment of FIG. 11 with the exception that amplifier 214 is coupledto the DAC module 212 and the output of the amplifier 214 provides theinput to the multiplexer 218.

FIG. 13 is a schematic block diagram of an embodiment of the analogconversion module 106 that includes the audio decoding module 210, theDAC module 212, the amplifier 214, and a second DAC module 222. In thisembodiment, when the RFIC is in the receive mode, the audio decodingmodule 210, the DAC module 212, and the amplifier 214 are active, whilethe DAC module 222 is inactive and when the RFIC is in the transmitmode, audio decoding module 210, the DAC module 212, and the amplifier214 are inactive, while the DAC module 222 is active.

When the RFIC is in the receive mode, the audio decoding module 210decodes the digital receive audio signals 146 in accordance with anaudio decoding scheme, which may be A-law pulse code demodulation, μ-lawpulse code demodulation, and continuous variable slope deltademodulation. In one embodiment, the audio decoding module 210 mayinclude an input for receiving an audio decoding selection signal 212that indicates the particular type of audio decoding to be performed.The DAC module 212 may include one or more digital to analog converts toconvert the decoded receive audio signals into analog decoded audiosignals. The amplifier 214 amplifies the analog decoded audio signals inaccordance with a pre-determined gain setting and/or an automatic gaincontrol setting to produce the receive electrical signals 148.

When the RFIC is in the transmit mode, the DAC module 222 converts thedigital transmit baseband or low IF signals 126 into analog transmitbaseband or low IF signals 128. The transmit baseband or low IF signals126 may include in-phase components and quadrature components. In suchan instance, the DAC module 222 would include two digital to analogconverters: one for the in-phase components and another for thequadrature components.

FIG. 14 is a schematic block diagram of an embodiment of the analogconversion module 106 that includes the audio decoding module 210, theDAC module 212, the amplifier 214, the second DAC module 222, anamplifier 224 or a digital amplifier 226. In this embodiment, when theRFIC is in the receive mode, the audio decoding module 210, the DACmodule 212, and the amplifier 214 are active, while the DAC module 222,the amplifier 224, and the digital amplifier 226 are inactive and whenthe RFIC is in the transmit mode, audio decoding module 210, the DACmodule 212, and the amplifier 214 are inactive, while the DAC module222, the amplifier 224, and the digital amplifier 226 are active.

When the RFIC is in the receive mode, the audio decoding module 210decodes the digital receive audio signals 146 in accordance with anaudio decoding scheme, which may be A-law pulse code demodulation, μ-lawpulse code demodulation, and continuous variable slope deltademodulation. In one embodiment, the audio decoding module 210 mayinclude an input for receiving an audio decoding selection signal 212that indicates the particular type of audio decoding to be performed.The DAC module 212 may include one or more digital to analog converts toconvert the decoded receive audio signals into analog decoded audiosignals. The amplifier 214 amplifies the analog decoded audio signals inaccordance with a pre-determined gain setting and/or an automatic gaincontrol setting to produce the receive electrical signals 148.

When the RFIC is in the transmit mode, the DAC module 222 converts thedigital transmit baseband or low IF signals 126 into pre-amplifiedanalog transmit baseband or low IF signals. In one embodiment, theamplifier 224 amplifies the pre-amplified analog transmit baseband orlow IF signals to produce the analog transmit baseband or low IF signals128. In an alternate embodiment, the digital amplifier 226 amplifies thedigital transmit baseband or low IF signals 126 prior to the DAC module222 converting the signals into the analog transmit baseband or low IFsignals 128.

FIG. 15 is a schematic block diagram of a radio transmitter integratedcircuit that includes the transmit acoustic transducer circuit 100, adigital conversion module 240, and the transmit baseband processingmodule 104. In this embodiment, the transmit acoustic transducer circuit100 converts transmit sound waves 118 into transmit electrical signals120. The digital conversion module 240, which may be implemented viaamplifier 170, analog to digital conversion module 174, and audioencoding module of FIGS. 8 and 9, converts the transmit electricalsignals 120 into the digital transmit audio signals 240.

The transmit baseband processing module 104 converts the digitaltransmit audio signals 122 into the digital transmit baseband or low IFsignals 126. Note that the radio transmitter integrated circuit mayfurther include an analog conversion module, which may include DACmodule 222 of FIGS. 13 and 14, an up-conversion module 108, and/or apower amplifier circuit 110. Further note that the analog conversionmodule may include amplifier 224 and/or digital amplifier 226 of FIG.14.

FIG. 16 is a schematic block diagram of a radio receiver integratedcircuit that includes a digital conversion module 248, the receivebaseband processing module 115, an analog conversion module 244, and thereceive acoustic transducer circuit 116. The digital conversion module248, which may be implemented via the ADC module 194 of FIGS. 8 and 9,converts the down-converted signals 142 into the digital receivebaseband or low IF signals 144. Note that the digital conversion module248 may further include amplifier 190 and/or digital amplifier 196.

The receive baseband processing module 115 convert the digital receivebaseband or low IF signals 144 into the digital receive audio signals146. The analog conversion module 244, which may be implemented viaaudio decoding module 210, DAC module 212, and amplifier 214 of FIGS. 13and 14, converts the digital receive audio signals 146 into the receiveelectrical signals 148. The receive acoustic transducer circuit 116converts the receive electrical signals 148 into receive sound waves150. Note that the radio receiver integrated circuit may further includethe down-conversion module 114 and the low noise amplifier circuit 112.

As may be used herein, the terms “substantially” and “approximately”provides an industry-accepted tolerance for its corresponding termand/or relativity between items. Such an industry-accepted toleranceranges from less than one percent to fifty percent and corresponds to,but is not limited to, component values, integrated circuit processvariations, temperature variations, rise and fall times, and/or thermalnoise. Such relativity between items ranges from a difference of a fewpercent to magnitude differences. As may also be used herein, theterm(s) “coupled to” and/or “coupling” and/or includes direct couplingbetween items and/or indirect coupling between items via an interveningitem (e.g., an item includes, but is not limited to, a component, anelement, a circuit, and/or a module) where, for indirect coupling, theintervening item does not modify the information of a signal but mayadjust its current level, voltage level, and/or power level. As mayfurther be used herein, inferred coupling (i.e., where one element iscoupled to another element by inference) includes direct and indirectcoupling between two items in the same manner as “coupled to”. As mayeven further be used herein, the term “operable to” indicates that anitem includes one or more of power connections, input(s), output(s),etc., to perform one or more its corresponding functions and may furtherinclude inferred coupling to one or more other items. As may stillfurther be used herein, the term “associated with”, includes directand/or indirect coupling of separate items and/or one item beingembedded within another item. As may be used herein, the term “comparesfavorably”, indicates that a comparison between two or more items,signals, etc., provides a desired relationship. For example, when thedesired relationship is that signal 1 has a greater magnitude thansignal 2, a favorable comparison may be achieved when the magnitude ofsignal 1 is greater than that of signal 2 or when the magnitude ofsignal 2 is less than that of signal 1.

The present invention has also been described above with the aid ofmethod steps illustrating the performance of specified functions andrelationships thereof. The boundaries and sequence of these functionalbuilding blocks and method steps have been arbitrarily defined hereinfor convenience of description. Alternate boundaries and sequences canbe defined so long as the specified functions and relationships areappropriately performed. Any such alternate boundaries or sequences arethus within the scope and spirit of the claimed invention.

The present invention has been described above with the aid offunctional building blocks illustrating the performance of certainsignificant functions. The boundaries of these functional buildingblocks have been arbitrarily defined for convenience of description.Alternate boundaries could be defined as long as the certain significantfunctions are appropriately performed. Similarly, flow diagram blocksmay also have been arbitrarily defined herein to illustrate certainsignificant functionality. To the extent used, the flow diagram blockboundaries and sequence could have been defined otherwise and stillperform the certain significant functionality. Such alternatedefinitions of both functional building blocks and flow diagram blocksand sequences are thus within the scope and spirit of the claimedinvention. One of average skill in the art will also recognize that thefunctional building blocks, and other illustrative blocks, modules andcomponents herein, can be implemented as illustrated or by discretecomponents, application specific integrated circuits, processorsexecuting appropriate software and the like or any combination thereof.

1. An apparatus comprising: a transmit acoustic transducer circuitcoupled to convert acoustic waves into an electrical audio signal; and adigital conversion module coupled to the transmit acoustic transducercircuit to convert the electrical audio signal into a digital audiosignal and also coupled to convert a down-converted receive signal intoa digital receive baseband or intermediate frequency (IF) signal, thedigital conversion module including a combining module to combine theelectrical audio signal with the down-converted receive signal toproduce a combined signal, an analog to digital conversion modulecoupled to convert the combined signal into a digital combined signal,and a separation module coupled to separate the digital combined signalinto the digital audio signal and the digital receive baseband or IFsignal.
 2. The apparatus of claim 1 further comprising: a transmitbaseband processing module coupled to the digital conversion module toconvert the digital audio signal into a digital transmit baseband or IFsignal; and a receive baseband processing module coupled to convert thedigital receive baseband or IF signal into a digital receive signal. 3.The apparatus of claim 2 further comprising: an analog conversion modulecoupled to the transmit baseband processing module to convert thedigital transmit baseband or IF signal into an analog transmit basebandor IF signal and coupled to the receive baseband processing module toconvert the digital receive signal into an analog receive signal.
 4. Theapparatus of claim 3 further comprising: an up-conversion module coupledto the analog conversion module to convert the analog transmit basebandor IF signal into an up-converted signal; and a power amplifier coupledto the up-conversion module to amplify the up-converted signal toproduce a transmit signal.
 5. The apparatus of claim 4 furthercomprising: a receive acoustic transducer circuit coupled to the analogconversion module to convert the analog receive signal into receiveacoustic waves.
 6. The apparatus of claim 1, wherein the transmitacoustic transducer circuit includes a transducer and a bias circuitcoupled to the transducer, in which the transducer converts the acousticwaves into the electrical audio signal based on biasing provided by thebias circuit.
 7. The apparatus of claim 6, wherein the transducerincludes one of a capacitive transducer, a MicroelectromechanicalSystems (MEMs) microphone or a floating electrode capacitive microphone.8. The apparatus of claim 1, wherein the digital conversion modulefurther includes an audio encoding module coupled to encode the digitalaudio signal.
 9. The apparatus of claim 8, wherein the audio encodingmodule further includes an input for receiving an audio encodingselection signal, in which the audio encoding selection signal indicatesone of A-law pulse code modulation, μ-law pulse code modulation, orcontinuous variable slope delta modulation to be performed for encoding.10. A method comprising: converting acoustic waves into an electricalaudio signal in a transmit acoustic transducer circuit; combining theelectrical audio signal with a down-converted receive signal to producea combined signal in a digital conversion module; converting thecombined signal into a digital combined signal in the digital conversionmodule; and separating the digital combined signal into a digital audiosignal and a digital receive baseband or intermediate frequency (IF)signal in the digital conversion module, wherein the electrical audiosignal is converted into the digital audio signal and the down-convertedreceive signal is converted into the digital receive baseband or IFsignal in the digital conversion module.
 11. The method of claim 10further comprising: converting the digital audio signal into a digitaltransmit baseband or IF signal; and converting the digital receivebaseband or IF signal into a digital receive signal.
 12. The method ofclaim 11 further comprising: converting the digital transmit baseband orIF signal into an analog transmit baseband or IF signal; and convertingthe digital receive signal into an analog receive signal.
 13. The methodof claim 12 further comprising: converting the analog transmit basebandor IF signal into an up-converted signal; and amplifying theup-converted signal to produce a transmit signal.
 14. The method ofclaim 13 further comprising: converting the analog receive signal intoreceive acoustic waves.
 15. The method of claim 10, wherein convertingthe acoustic waves into the electrical audio signal is performed byconverting the acoustic waves into the electrical audio signal based onbiasing provided by a bias circuit to a transducer.
 16. The method ofclaim 15, wherein converting the acoustic waves into the electricalaudio signal is performed by the transducer that includes one of acapacitive transducer, a Microelectromechanical Systems (MEMs)microphone or a floating electrode capacitive microphone.
 17. The methodof claim 10, further comprising encoding to encode the digital audiosignal.
 18. The method of claim 17, wherein the encoding furtherincludes receiving an audio encoding selection signal, in which theaudio encoding selection signal indicates one of A-law pulse codemodulation, μ-law pulse code modulation, or continuous variable slopedelta modulation to be performed for the encoding.